Sunday, April 7, 2013

A final view to the south at Seal Rock State Park. The head on the middle horizon is Cape Perpetua, and while I've posted a few photos from there in this series- I'll have to review to see which ones- I'm thinking I'll post some more in the coming week. The rock there is Yachats Basalt, which is from a different source and age than both the CRB here, and the Siletz River Volcanics that form the basement of the Coast Range.

I have realized, as I get older, that some of my most creative moments come when I'm not really awake- either dozing off, struggling to stay awake when I've over-extended myself, and most especially first thing in the morning, when I'm struggling to reassemble my shattered consciousness after a good night's sleep.

Yesterday as I woke up, I was pondering the possibility of a sheath of steam around the margins of the intrusion keeping the upper portion of Elephant Rock better insulated, thus creating the down-to-up cooling gradient. I said "creative," not necessarily "sensible." Though nothing about that feature is sensible, that guess just seems like a stretch to me.

But this morning, the phrase "ball-and-pillow," which I tossed out yesterday to somewhat acerbically compare this to a secondary sedimentary structure, was zinging around my head, smashing the carefully arranged glassware in my mind. Wait... what if it wasn't tabular? (I realized I've never defined that term- it means relatively large in two dimensions, and small in the other. So sheet or tablet-like.) In other words, neither a dike nor a sill. What if, like true ball-and-pillow structures, its overall shape was more like a horizontally-oriented cylinder?

Okay, it's crude and schematic, but in terms of plausibility, I'm happier with this than anything else I've come up with. I'm certainly not going to argue this is "correct," but it makes sense. And that's something of a relief.

This is one of the unexpected pleasures of this series: it forces me to look anew at things I've seen countless times before, and think about trying to make sense of things I've never really considered. The columns at Elephant Rock, for example, are a feature I've pointed out to others many times, but until two days ago, had never really thought about in terms of their perplexing orientation. And this was in fact the very first "geologic spot" in Oregon I visited, about a month into Spring Term of 1980.

Another one of my non-standard geologic principles is that of Geologic Time: "It took millions to billions of years to create some outcrops. Don't expect to be able to figure them out in a few minutes." Indeed, sometimes it can take decades to even recognize there's a problem that needs solved.